1. Field of the Invention
The present invention pertains to an improved method of hydraulic fracturing earth formations to produce fluids therefrom by controlling the rate of injection to form the desired fracture length and fracture width in moderate permeability and high permeability formations.
2. Background
In the hydraulic fracturing of earth formations to stimulate the production of oil and gas from wells, conventional practice results in the injection of fluids into the formation at a rate which is limited by the available pumping power at the well site. A prescribed rate of injection is usually carried out using the available power as the treatment pressure rises to the maximum permitted by such available power.
In earth formations of relatively low permeability, where the production of fluids from the fractured area will be controlled primarily by fracture length, the constant rate of injection method is usually satisfactory. However, in relatively high permeability formations, in which the production of fluids from the fractured zone or area is more a function of fracture conductivity, increased fracture length is not as important or significant as increased fracture width. Accordingly, the present invention is directed to an improved method for controlling the rate of hydraulic fluid injection to provide a fracture which will maximize the production of fluids from earth formations having moderate to high permeability.